/*
 * Copyright 1998-2015 University Corporation for Atmospheric Research/Unidata
 *
 *   Portions of this software were developed by the Unidata Program at the
 *   University Corporation for Atmospheric Research.
 *
 *   Access and use of this software shall impose the following obligations
 *   and understandings on the user. The user is granted the right, without
 *   any fee or cost, to use, copy, modify, alter, enhance and distribute
 *   this software, and any derivative works thereof, and its supporting
 *   documentation for any purpose whatsoever, provided that this entire
 *   notice appears in all copies of the software, derivative works and
 *   supporting documentation.  Further, UCAR requests that the user credit
 *   UCAR/Unidata in any publications that result from the use of this
 *   software or in any product that includes this software. The names UCAR
 *   and/or Unidata, however, may not be used in any advertising or publicity
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 */
package thredds.inventory.partition;

import thredds.inventory.CollectionAbstract;
import thredds.inventory.DateExtractor;
import thredds.inventory.MFile;
import thredds.inventory.MFileIterator;
import ucar.nc2.util.CloseableIterator;

import java.io.IOException;

/**
* A Directory Collection of MFiles, the MFiles are found from an existing ncx2 index
* Scans files only when asked
* @author John
* @since 12/9/13
*/
class DirectoryCollectionFromIndex extends CollectionAbstract {
  final DirectoryBuilder builder;
  final IndexReader indexReader;

  DirectoryCollectionFromIndex(DirectoryBuilder builder, DateExtractor dateExtractor, IndexReader indexReader, org.slf4j.Logger logger) {
    super(builder.getPartitionName(), logger);
    setDateExtractor(dateExtractor);
    setRoot(builder.getDir().toString());
    this.builder = builder;
    this.indexReader = indexReader;
  }

  @Override
  public CloseableIterator<MFile> getFileIterator() throws IOException {
    return new MFileIterator( getFilesSorted().iterator(), null);
  }

  @Override
  public String getRoot() {
    return builder.getDir().toString();
  }

  @Override
  public void close() { }

  @Override
  public Iterable<MFile> getFilesSorted() throws IOException {
    return builder.readFilesFromIndex(indexReader);  // LOOK guarenteed sorted ??
  }

}